On February 5, Bob Arum announced Timothy Bradley as Pacquiao’s next opponent on June 9 for his WBO Welterweight title, after another failed negotiation attempt with Floyd Mayweather Jr. on Cinco De Mayo. During the final press conference, WBO President Francisco “Paco” Valcarcel awarded Pacquiao with WBO Diamond Ring in recognition of Pacquiao as the WBO Best Pound-for-Pound Fighter of the Decade.

Pacquiao lost the bout in a controversial split decision, scoring 115-113, 113-115 and 113-115 from the three judges. The decision was booed by the crowd and criticized by many news outlets who were independently scoring the fight. However, Pacquiao was gracious in defeat and Bradley called for a rematch. Following the decision, many analysts called the decision a corruption of the sport. ESPN.com scored the fight 119-109 for Pacquiao. HBO’s unofficial judge, Harold Lederman, also had it 119-109 for Pacquiao. Most ring side media also scored the fight in favor of Pacquiao.

Four days after the fight, Valcarcel said in a statement on June 13, 2012 that although the WBO did not doubt the ability of the scoring judges, the WBO’s Championship Committee would review the video of the fight with five independent, competent, and recognized international judges and make a recommendation. On June 21, 2012, the five WBO Championship Committee judges on the review panel announced that Pacquiao should have won his controversial defeat, with all scoring the fight unanimously in Pacquiao’s favor — 117-111, 117-111, 118-111.